Question

I am trying to export my repeater to excel and here is my code…

    StringWriter sw = new StringWriter();
    HtmlTextWriter htw = new HtmlTextWriter(sw);
    string attachment = "attachment; filename=file.xls";
    Response.ClearContent();
    Response.AddHeader("content-disposition", attachment);
    Response.ContentType = "application/vnd.ms-excel";
    rpt.RenderControl(htw);
    Response.Write(sw.ToString());
    Response.Flush();
    Response.End();

When I am trying to open file getting this error

The file you are trying to open, 'file.xls', is in a different format than specified 
by   the file extension. Verify that the file is not Corrupted and is from a trusted 
source   before opening the file. Do you want to open the file now?
Yes   No Help option are available

What’s wrong in my code or What I have to do resolve this issue.
Thanks

Answer 1

You are setting the content type to application/vnd.ms-excel but you are sending HTML contents in the response stream when you call the RenderContents method. You might need a library to generate Excel files.